It's an understood reality that, in any association, members come in all different shapes and sizes, so to speak. One size does not fit all, so segmentation is crucial to appealing to a variety of member motivations.

However, some associations struggle with taking full advantage of segmentation because, well, they're too nice. "When you're in an association, you want to be perceived as being fair, and so [segmentation is] a hard thing to do," says Robbie Kellman Baxter, president of Peninsula Strategies and author of The Membership Economy. Segmenting your association's member market means more than just dividing people into groups. It also means placing more value on some of those groups than others.

"Not that you don't want to treat everybody well, but you want to focus in on the places where you're going to have the biggest positive impact on the health of the organization as a whole," Baxter says.

That focus is as important to engaging existing members as it is to recruiting new ones. "Associations say things like, 'We want to have more engagement with our members.' And the question I always ask is, 'Well, which ones?' Because, if you want more engagement with everybody, that's going to be really expensive."

Different member segments can play different roles, too. While one group might be high-end users willing to spend money on premium resources, another might be a low-spend group that instead provides value through volume. Take LinkedIn, for example.

"Even if I never pay, the fact that I am a free, nonpaying member on LinkedIn makes the LinkedIn service more valuable to the people who do pay, because they access my information, my network," Baxter says. "It's richer because everybody else is in there."

[This article was originally published in the Associations Now print edition, titled "Who Matters Most?"]